The 19-year-old arrived at Anfield from Aberdeen last summer and was immediately integrated into the first team setup under Jurgen Klopp.
Ramsay would provide backup to Trent Alexander-Arnold, but the Scotland international only made two first-team appearances for the Reds due to injury.
The right-back accumulated just 93 minutes in the EFL Cup and Champions League, while also making the bench once in the Premier League against Tottenham Hotspur in November.
A serious knee injury subsequently ruled Ramsay out for the remainder of the campaign, but he is understood to be on the verge of a return and will ply his trade in the Championship next season.
"I'm delighted to join Preston North End. The Championship is a top league as everyone knows and the main thing for me is trying to get game time, and I'm going to be able to do that at a good club. I can't wait to get started," Ramsay told pnefc.net.
"I'm happy to be getting the opportunity to get regular game time in a good league, which is important for me. I just need to work hard and try to play as many games as I can.
"There were quite a few clubs interested, but when I spoke to the manager (Ryan Lowe), everything that he said was spot on. The way the team plays, they like to play attacking football, keep the ball and get forward.
"I think that suits my game because I can score and assist goals, and I like getting at people. Ultimately Preston suited me the best."
Preston head coach Ryan Lowe added: "I'm really pleased we've managed to get Calvin through the door on a season-long loan.
"He fills a position we've been looking to fill for a while as it gives us good competition down that right-hand side where Brad Potts has obviously been fantastic.It gives us options now, too. We've got a right back in the building as well as someone who can play right wing back.
"He's energetic, he's dynamic, and he can get himself up and down the pitch. Liverpool obviously invested a lot of money in him after he came through at Aberdeen so we know the quality he's got."
Before joining Liverpool in a deal that could rise to £6.5m, Ramsay recorded one goal and nine assists in 39 games for Aberdeen and was named the Scottish Football Writers' Association Young Player of the Year for the 2021-22 season.
With Ramsay heading for Deepdale and James Milner departing on a free transfer, Alexander-Arnold is short of cover at right-back at Anfield, but Fulham's Kenny Tete and Ajax's Jurrien Timber have been linked with moves to Merseyside.